Xylylenediamine is a compound useful as a raw material for polyamide resin, an epoxy resin curing agent, and a raw material for isocyanate compound or the like. Polyamide resin using xylylenediamine as a main diamine component are excellent in mechanical properties such as strength, elastic modulus and others, and are therefore useful as various molding materials. In addition, the polyamide resins are excellent in gas barrier performance against oxygen, carbon dioxide gas and others, and are therefore useful also as packaging materials. However, it is known that xylylenediamine is apt to be changed in quality and colored due to light, heat, oxygen, or the like.
In addition, the polyamide resins using xylylenediamine as a main diamine component involve such a problem that when exposed to a high-temperature atmosphere in a molten state or solid state, they are apt to be colored yellow, and their use was sometimes limited depending upon an application.
As a method for solving the above-described problem, for example, PTL 1 discloses a polyamide resin resulting from polycondensation of a diamine containing xylylenediamine with a specified aliphatic dicarboxylic acid, in which a purity of the xylylenediamine used as the raw material diamine is 99.9% by weight or more and on heating the resin under a prescribed condition, a difference of a yellowness index (YI value) before and after heating is within 5.
Meanwhile, in order to improve molding processability or the like of a polyamide resin, it is known to add a crystal nucleating agent to the polyamide resin, thereby improving a crystallization rate (PTL 2). In addition, for improving the chemical resistance and the strength of polyamide resin, a method of adding a crystal nucleating agent or a resin component having high crystallinity to polyamide resin to thereby increase the degree of crystallization of the resin is known. However, the case where a crystal nucleating agent or the like is added to a polyamide resin requires an additional step of mixing the crystal nucleating agent to the polyamide resin before molding. In addition, when the dispersed condition of the crystal nucleating agent is nonuniform in the polyamide resin, there is a concern that mechanical physical properties and transparency of the molded articles of a composition containing a polyamide resin are often lowered.